INTRODUCTORY ESSAY. 53 Moon's catalogue of the plants of Ceylon is also a bare list of names. Many of these are evidently erroneously applied, so that it is impossible to make use of them. Fortunately, however, this is of little consequence, as we have no lack of specimens from Ceylon. Moon's collections were excellent; but he docs not appear to have sent any specimens to Europe. Dr. Voigt's * Hortus Suburbanus Calcuttensis/ published at Calcutta in 1845, is, for the same reason, not available as a work of reference, nor can we refrain from expressing our re- gret that talents of so high an order should have been devoted to a work of so little practical use. Dr. Lindley's invaluable < Genera and Spbcies of Orchidcous Plants3 contains descriptions of all the Indian Orchidese • cpl- lectcd by Wallich and his predecessors; and in the published parts of the 'JFolia Orchidacca' (now in course of publication) we have a complete account of many of the genera, drawn up after a most laborious and critical examination of all the materials accessible up to the latest day. Our own collectiona arc being thus published, and we consider ourselves highly fortunate in their falling into such able hands*. Dr. Lindley has further rendered essential service to Indian botany by nu- merous descriptions and figures of Indian plants that have appeared in various illustrated periodicals. He laboured in* dcfatigably iu the distribution of the great Wallichian Her- barium; his elementary books on botany, and his great work, the ' Vegetable Kingdom/ arc indispensable both to botanical students and to proficients; whilst, by the scientific direction he has given to the study and practice of horticulture, as an author and as secretary of the Horticultural Society of Lon- don, he has been the means of rendering English botanists familiar with the plants, of India in a living state, to an ex- tent that would have been thought visionary a few years ago. * The annlysiM of plants of this Order, in a dried state, is a work of the ut- most difficulty; and we would urg« upon botanists in India the necessity of drawing and describing the fresh specimens, and of preserving tile flowery (as of all plants whoeo parts are injured by the operation of pressing and drying) in Hpirits or acid.